The invention provides heat-resisting and wear-resisting alloy steel. The heat-resisting and wear-resisting alloy steel is prepared from, by weight, 0.25%-0.35% of C, 17%-19% of Cr, 17%-19% of Mn, 0.6%-1.2% of Si, 0.6%-1.0% of Ti, 1.2%-2.0% of W, 0-0.02% of P, 0-0.02% of S, 0.05%-0.25% of Y, 0.05%-0.25% of Ce, 0.025%-0.05% of Al and the balance Fe. A preparation method of the heat-resisting and wear-resisting alloy steel comprises the steps that scrap steel, low-carbon ferrochromium and electrolytic manganese are placed in a furnace to be molten; oxygen blowing is conducted when the temperature of molten steel is higher than 1580 DEG C; 70% of aluminum, 20% of silicon and 10% of calcium wires are inserted into per ton of molten steel, composite powder containing 1% of carbon, 50% of silicon and 49% of calcium is added onto the liquid surface, slagging is conducted, ferrotitanium and ferrotungsten are added, yttrium-cerium-based mixture rare earth is added to the bottom of a steel ladle, and the tapping temperature is 1620-1640 DEG C; a casting is cast at the temperature of 1530-1580 DEG C; and heat treatment is conducted at the temperature of 1050-1100 DEG C, the casting is placed in water after being discharged out of the furnace, and the water temperature is not higher than 38 DEG C. According to the heat-resisting and wear-resisting alloy steel and the preparation method thereof, through the optimal design of the elements, melt purification and optimization of the heat treatment technique, the steel which is high in heat strength, abrasion resistance and heat resistance is obtained.